Electric switch



June 17, 1952 w. J. HUBBARD ELECTRIC SWITCH Filed Sept. 12, 1947INVENTOR. fi/adm BY v flsfifiefdarope ATTORNEY Patented June 17, 1952 rUNITED STATES PATENT OFFICE ELECTRIC SWITCH William J. Hubbard, Toledo,Ohio Application September 12, 1947, Serial No. 773,720

2 Claims. 1

The present invention relates to electrical switches, and moreparticularly to a novel type of automatic, self-throwing switch which isoperable upon tilting movement of the switch itself to make and/or breakan electrical connection.

The switch of this invention can be readily adapted for a wide varietyof uses in a great many fields. For example, I have found it to beparticularly well suited for use as a light control means in rearluggage and glov compartments and under hoods, etc., of automobileswhere it is desired to have the light turn on automatically whenever thecompartment is opened and to have the light turn oil when thecompartment is closed.

Heretoiore, a great deal of difficulty has been encountered with theswitches used for this purpose, due to failure of the switches under thegreat number of repeated operations to which they are subjected duringthe life of the car; because of corrosion or oxidation of the contactpoints resulting from the presence of moisture and unquenched spark inthe switch unit; and because replacement or repair of the prior usedswitches has been both diilicult and expensive.

It is an aim of the present invention to provide a new type oftilt-operated switch for this purpose which will overcome all of theabove objections, which is of relatively simple construction, andinexpensive to produce; which is remarkably long lived, and practicallyindestructible, and yet can be readily and easily replaced if necessary.

Another object is the provision of a switch unit of this generalcharacter which, when tilted at an angle to the horizontal in onedirection, will close an electrical circuit and maintain it closed; andwhich, when tilted at an angle to the horizontal in another directionwill break the circuit and maintain it open.

Another object is to provide such a switch unit that is made up of ahousing having a conducting portion on or associated therewith, anelectrical contact within the housin and insulated therefrom, and amovable conductor also within the housing and in continuous contact withthe conducting portion associated therewith and movable into and out ofengagement with the insulated contact upon tilting of the switch unit.

Another object is the provision in a switch unit of such character of asupply of liquid adapted to'lubricate the movable contact and to dampenor restrict undesirabl movement thereof.

Still another object is to provide a combinalion, lightfand switchunit01 this same general 2 character, but in which a light bulb is mountedin the housing.

Other objects and advantages of the invention will become more apparentduring the course of the following description, when taken in connectionwith the accompanying drawings.

In the drawings, wherein like numerals are employed to designate likeparts throughout the same:

Fig. 1 is a fragmentary section taken through the rear luggagecompartment of an automobile, showing the lid of the compartment closedand the switch unit of the invention mounted on the inside thereof;

Fig. 2 is a perspective view on a larger scale of the switch andmounting shown in Fig. 1, but showing the position of the switch whenthe lid of the luggage compartment is raised to open position;

Fig. 3 is a section taken substantially on the line 3--3 in Fig. 2

Fig. 4 is a fragmentary section taken through the switch when it is inthe position shown in Fig. 1; and

Fig. 5 is a similar section taken through the switch when it is in theposition shown in Fig. 2.

Referring now more particularly to the drawings, there has beenillustrated therein a preferred form of combined-light and switch unitwhich is designated in its entirety by the numeral I0.

As best shown in Fig. 5 the unit I0 comprises a cylindrical metal casingor housing II which is closed at one end as at I2, and open at theopposite end to receive the base I3 of an incandescent lamp I4. The baseI3 carries a lead wire I5 in electrical contact therewith and is sealedinto the casing or housing I I by a suitable water vapor resistingcement or mastic I6 which also serves to insulate the wire I5 and baseI3 from the casing.

Carried within the sealed housing I I is a movable conductor, here shownin the form of a single ball I! which is free to run back and forth on,and in contact with the conductin wall I8 of the housing upon tiltingmovement of the housing from one side to the other of the horizontal.The ball is of sufllcient diameter to permit it to make an electricalconnection between the conducting wall II and a contact I9 on the lampbase I3 when it rolls into the position illustrated in Fig. 5.

As pointed out above, in the past considerable difliculty has beenexperienced with tilt type switches because of the tendency of thecontacts 3 and conductors to corrode and oxidize from exposure tomoisture and from sparking when contacts were made. According to thisinvention such difiiculties are overcome first by sealing the cylinderagainst the entrance of moisture and second by causing the ballconductor to run in a bath of lubricating fluid 20.

The sealing material [6 should be a moisture impermeable or a highlymoisture resistant substance such as a substantially solvent freesubstance including a partially polymerized olefin sulphide resin and athermosetting phenol formaldehyde resin mixed with a catalyst. Such aseal will not only prevent, or at least greatly retard, the ingress ofwater vapor, which would rust or corrode the conductor andcontacts,'into the cylinder, but will also seal the lubricating fluidtherein.

As here shown the lubricating fluid 20 is in the form of an oil and Iprefer to use silicone oil which flows freely at 70 F. and has a veryhigh flash point. The presence of this oil in the tube serves a twofoldpurpose. In the first place it lubricates and prevents rusting of theball l1, and in the second place it will act to quench the spark whenthe ball conductor ll makes the connection between the conducting walll8 of the cylinder and the contact l9. For this latter purpose it isimportant to have sufficient oil in the cylinder to cover the surfacesof the conductor I1 and the contact 19 when the switch is in theposition illustrated in Fig. 5.

Still another function of the liquid 20 is to dampen or retard movementof the ball I"! when the switch is in the position shown in Fig. 4. Thisis important because when the switch is in this position it isundesirable to have the conductor thrown into engagement with thecontact I9 by vibration or by bumping of the vehicle to which the switchis attached over rough roads and the like. Of course a similar resultcan be attained by using a cylinder ll of sufficient length, but Iprefer the damping action of the liquid which gives a positive controland permits the use of a much shorter cylinder.

Silicone oil is at present quite expensive and other oils, liquids oreven gases having suitable lubricating qualities and relatively highflash points and low flow points, may be used to accomplish all or someof the same purposes as the silicone oil. Of the oils, circuit breakeroil can be satisfactorily used in temperate climates.

The fluid 20 of this invention can also be advantageously used inswitches of different construction from the one illustrated here tolubricate and/or dampen unwanted movement of a movable conductor. Forexample, it will also prolong the life and increase the efficiency ofmercury type switches, or switches equipped with a hinged or swingingconductor.

In producing the particular switch units here described, the closureplate 2| can be formed as part of the cylinder l I, or it can besoldered into place during assembly of the unit. The incandescent lampcan, of course, be removably mounted in the open end of the cylinder inthe conventional manner, using a threaded lamp base and cylinder, or bybayonet slots and suitable lugs, if desired. With this arrangement,burned out bulbs could be readily replaced. However, my unit can be madeso inexpensively that I prefer to cement the lamp into the switchcylinder to form a sealed, composite, integral unit.

A convenient way of mounting the switch unit of the invention on the lidof a rear luggage compartment of an automobile has been illustrated inFig. 1. As here shown, a bracket 22 having a base plate 23 and a pair ofmounting arms 24 and 25 is secured to the inside of the lid 26 withscrews 21. The switch i0 is then mounted between outwardly curvedportions 28 of the arms and clamped in place by means of a bolt 29 andwing nut 30. A hot wire 3| from the electrical circuit of the automobileis connected to the lead wire 15, and a ground wire 32 is connected tothe bracket 22. The ground wire 32 can be omitted if desired because themetal bracket 22, clamped to the metal cylinder ll of the switch andscrewed to the metal lid 25 will provide a suitable ground.

With the switch 10 thus mounted on the automobile, and the lid 26 closedas shown in Fig. l, the ball conductor I! will be in the position shownin Fig. 4 and the lamp M will be out. However. when the lid of theluggage compartment is raised, as shown in Fig. 2, the switch will be inthe position illustrated in Fig. 4, and the conducting ball ll will rollalong and in contact with the conducting wall 18 of the cylinder I linto the position shown in Fig. 5, where it will complete the circuitbetween the cylinder I l, conductor H and contact l9 to light the lamp.

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as a preferred embodiment of the same. but thatvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

I claim:

1. An expendable switch unit comprising a metal cylinder, a platepermanently closing one end of said cylinder, an incandescent lamphaving a base extending into and substantially closing the opposite endof the cylinder and a contact on said base, a substantially solvent-freesealing material comprising a partially polymerized olefin sulphideresin and a thermosetting phenol formaldehyde resin mixed with acatalyst in the space between said base and said cylinder impermeablysealing the interior of the cylinder cementing said cylinder and saidlamp together into an integral unitary structure and insulating saidbase from said cylinder, a single metal ball within said cylinder freeto move in continuous contact with the wall thereof, and a supply ofhigh flash point low flow point lubricating oil also within saidcylinder in sufficient volume to cover the points of contact of saidball with said wall and said contact on the base of said lamp but freelymovable with the ball.

2. An expendable switch unit comprising a metal cylinder, a platepermanently closing one end of said cylinder, an incandescent lamphaving a base extending into and substantially closing the opposite endof the cylinder and a contact on said base, a substantially solvent-freesealing material comprising a partially polymerized olefin sulphideresin and a thermosetting phenol formaldehyde resin mixed with -acatalyst in the space between said base and said cylinder impernieablysealing the interior of the cylinder cementing said cylinder and saidlamp together into an integral unitary structure and insulating saidbase from said cylinder, a single metal ball within said cylinder freeto move in continuous contact with the wall thereof. and a supply of ahigh flash point silicone oil free flowing at --70 F. also within saidcylinder in suflicient volume to cover the points of contact of saidball with said wall and said contact on the base of said lamp NumberName Date but freely movable with the ball. 1,341,267 East May 25, 1920WILLIAM J. HUBBARD. 1,463,974 Schweitzer Aug. 7, 1923 1,719,742 AdamsJuly 2, 1929 REFERENCES CITED 5 2,107,570 Hobbs Feb. 8, 1933 Thefollowing references are of record in the 2,206,094 Hobbs July 1940 filef t t t; 2,228,456 Hobbs Jan. 14, 1941 2,277,352 Posey Mar. 24, 1942UNITED STATES PATENTS 2,382,646 McCarthy Aug. 14, 1945 Number Name Date10 2,487,433 Gardenhour Nov. 8, 1949 1,175,062 Johnson Mar. 14, 1916

